WPAWPA

NeuroimagingNeuroimaging

WPAWPA

Basic Principles of Brain Basic Principles of Brain ImagingImaging

• Some technique is used to measure a signal in Some technique is used to measure a signal in the brain (e.g., the degree to which an xray the brain (e.g., the degree to which an xray beam is attenuated in CT)beam is attenuated in CT)

• Brain is broken down into a grid of cubes Brain is broken down into a grid of cubes (voxels, or volume elements(voxels, or volume elements

• The voxels are converted to pixels (picture The voxels are converted to pixels (picture elements) so that the brain images can be elements) so that the brain images can be visualizedvisualized

• High speed computers are used to generate the High speed computers are used to generate the imagesimages

WPAWPA

Structural Imaging ToolsStructural Imaging Tools

• Computer Tomography (CT): Computer Tomography (CT): now largely surpassednow largely surpassed

• Magnetic Resonance Imaging Magnetic Resonance Imaging (MRI), also referred to as (MRI), also referred to as structural MR (sMR): used to structural MR (sMR): used to measure brain anatomymeasure brain anatomy

• Diffusion Tensor Imaging (DTI): Diffusion Tensor Imaging (DTI): used to measure white matter used to measure white matter tractstracts

WPAWPA

Three Types of MR Three Types of MR ImagesImages

T2 PD T1

WPAWPA

A A BrainBrain Disease:Disease:

CT scans CT scans showing showing ventricular ventricular enlargement in a enlargement in a patient withpatient withschizophreniaschizophrenia

WPAWPA

Consistent Replication: CT Consistent Replication: CT Studies of SchizophreniaStudies of Schizophrenia

WPAWPA

MR Images of Brain, MR Images of Brain, Ventricles, and HippocampusVentricles, and Hippocampus

Schizophrenia

Control

WPAWPA

Multimodal MR ImagingMultimodal MR Imaging

T2 PD T1

WPAWPA

Automated Tissue Automated Tissue ClassificationClassification

WPAWPA

Classified ImagesClassified Images

Continuous Discrete